Mikey: Death of the best 350 and 500 for a six...the #2305

[xctasy]

Mikeywanted to know

And Xecute- if you can post the ideal venturi size, etc. numbers for an OZ 2V head, that would be really cool.

Is the Falcon 6 motor handbook a good resource for such calculations?

The FS hand book is a winner. It errs on the side of caution. Theres nothing extensive on the 2v though. I haven't got the book yet. Maybee I be a bit more carefull on what I say.

Boy, did I think I hit paydirt last week. There was a discussion on 2305 series carbs way back somewhere which I remember, but the main piece was that it is a sequential carb, sort of a cut-down of the most popular 4160 550cfm vac sec for the 350, and a 4160 (part number 3310) 750 cfm 4-bbl vac sec, for the 500 2-bbl. Sounds like it's just the carb for us guys worried about too much carb for the cubes. Does any one know when it was canned, and how easy they are to find?

Mikey, I think the 2305 500 cfm is the best carb. It's basically half of the best V8 street strip carb ever made. It flows a true 354 cfm at 1.5" Hg, and half of its 221 hp capability is made on the first barrel. So long as the secondary comes in nicley, its the one to have. A Weber DGAS 38 would be a close match. Then a 465 cfm 4-bbl or 500 cfm simultanoues PN 4412 would be the second and third options. I believe the 390 cfm is too restricted in the venturi area, giving a very strong signal in both priamry and secondary circuits. On a six, which has great idle and off-idle vacuum, I'd shy away from it. Okay on a 170 cube V-6, but not on a bigger straight six. A 390 may be the 'ducks guts on a 140 Vega, 2 liter Pinto, 2300 Lima, 215 Buick or Rover 3500/TR7 V8, but the intake manifolds are nice and small, with good distribution. The 2V six has poorer fuel air distribution than those and way too much plenumb area where there is no downward flow to gain gas speed. But Mustangaroo has run one and I haven't. What makes me the expert?

Oh, if you want power levels and throad areas and venturi sizes, then just check lines 9 and 16 of the chart I set up here.

Back on to the 2305, then.

http://fordsix.com/forum/viewtopic.php?t=7015
Fittingly chaotic, but it's all there. Maximum power per barrel is on the right

From http://www.allpar.com/omni/testimonials.html

Gary Howell's Rampage: The Rampage has had several carburetors on it. The one that I liked the best was the Holley 2305 series progressive 2bbl. Vibration destoryed several of them. The carb. on it now is a reworked factory 5200 series Holley, Barry Grant fuel systems did a stage 3 rebuild on it. They wouldn't give me any flow numbers on it, but it should be in the low 400 cfm range.

Another post http://www.225.ca/tech/jstk001.htm, from our brothers at theSlantSixSite:-

Another route to go if you have a modified engine would be the Holley 2305. The 350 cfm version should do quite nicely on a mild engine. The 500 would only be for more heavily modified motors. The 350 may sound like it's only 40 cfm smaller than the Holley 390 cfm 4 bbl, but it isn't. Holley tests its 2 bbl and 4 bbl carburetors differently. They use a 1.5" of Hg (mercury) pressure drop for 4 bbl, while 2 bbl carburetor flow numbers are generated at 3" of Hg. So the difference is actually much greater than the 40 cfm that the numbers indicate. There is a formula to convert between the two, but I don't have it handy. One other thing about this carburetor: It uses annular discharge booster venturis which help give a better metering signal. This lets you get the jetting closer to optimum without suffering bogs and hesitation. If I can stand to part with the money, I may try this in place of my 390 4 bbl to test the results. If not I'll try a Holley/Weber carburetor off of a Pinto or Vega.

Update! The Holley 2305 is no longer available. They didn't sell well and were discontinued.

And from the last site, http://groups.yahoo.com/group/locost/message/829?source=1:-

There was a question a few days ago about changing a Pinto from a Holley-Weber to a progressive Holley 2305. The Holley-Weber was listed as
having 180 cfm. According to my Holley catalog, the 5200 range from 230 to 280 cfm, depending on application.
There seemed to be some misconception about the 2305 as to their
configuration. At first glance they do look like the 2300, but the
throttle shafts are different. They are thru the short side of the Holley
base, not the long side, and they are available either as 350 or 500 cfm.
They are intended specifically for small 6 and 4 cyl applications, and they
do work. One could maybe pick up another 30-50 cfm on the 5200 series with
some judicious polishing, but the 350 would be a better starting place for
modifications.

 

[Anonymous]

Cool! Now to find one.... Or at least something close.

But Mustangaroo has run one and I haven't. What makes me the expert?

You just seem to have a lot of info in general. We Just need to run a tap to your brain and pull a nice cold beer of knowledge once in awhile. And lot's of other people seem to ask you stuff. When in Rome...

BTW- the Falcon 6 book doesn't make much coverage of the OZ heads. It sticks with the U.S. heads. There's a lot of other useful tips in there. I Read it cover-to-cover with hi-liter pen in hand the day it showed up.

--mikey

 

[Anonymous]

HI there a ? for the gifted i have a 350 holley with 60jets it was on my 250 2v pre-cross and lacked power but was very strong in fuel smell and now like my matey tim i run a 500holley with 68 jets but same prob very strong in fuel and it wont run vell .
the bore is 60thou starnded crank deck droped 10thou camcode 63602 in26-64 ex66-24.basicil i can get the car running right i have a elec dizzy to fit and maybe drop the jets down or what ever i dont know any idears please

 

[Anonymous]

GS pack
Rob I wish could tell you waht the fuel smell on both is from. The Carb re-builder who supplied my 500 Holley siad that he would be very surprised if going down in jets size on a 500 did not cause a flat spot when driving my car (I went from 71 to 68). It does especially if it not completely warm, but is liveable.
Dont think can compare the 350 jets to 500 jets. (any one else??)

 

[Anonymous]

Just a word in reply to the top entries about the 390 cfm the bore is 36.5 mm almost exactly the same bore as the twin Stromberg that the 2Vs came with.
I think they are definitley too small for power off idle up through the lower revs (as a number have suggested) both the 350 and the 500 both with bigger bore give a noticable increase over the old Stromberg in this area (especially and most noticably the 350). The 390 might make up for this when the secondaries kick in but a 450 4bbl would have to be better.
I like the idea of a 500cfm four barrel but havent seen too many around.

 

[xctasy]

1. Float level should be the minimum to produce no off idle stumbling,
2. an idle corrector jet that is greater than 16 or 17 thou, and less than the stock one for the PN 7448 and PN 4412.

3. Very rich idle is a common problem with these carbs on a smaller engine than the 327 to 396/402 cube 2-bbl engines they were designed for.
4. 4-cyl guys in America have found the carb runs cleaner than the 32/36 Weber carby, and it's all down to jet size.

5. Heres the spec on 2-liter Pinto/Capri/Cortina/Escorts, with a gas flowed head and the Erson 134 cam, of wilder specs than yours but similar 50 thou figures, G/Spack.

The stock 350 cfm main jet came in at 63,

The 500 Holley was 74.

I'd be sure a six sucks much more vaccum than a four, but I'd be suprised if the jet sizes would be smaller if the idle corrector air-blead was smaller.

6. Talk to the specialist. A Holley has four different booster venturis, and there are several types of Holley for the Australasian market. Some had booster venturis of the economaster type, and were rated at a different cfm. Check the part numbers. The Holley Performance book lists what should be there. If there is an air leak in the base, or the wrong cam is used on the throttle, the calibration changes.

7. Are you guys using a proper air-cleaner,

8. and is the choke spring strong enough?

 

[Anonymous]

Did you say 74 stock jet size for 500. I thought it was 71 althought I have heard 70, 71, 72 but not 74. If 74 is right then both me and GS pack are way under size ay 68. There was a big visible difference between 71 and 68 (and economy). I think I better come up at least a few sizes.
Cheers Tim

 

[Anonymous]

GEZ thats a bit to check on ,I,ll wait to see how yours go tim before i go up in jets .
i dont belive there is any air leaks not that i have found as yet any way,as for air cleaner i have a 12" redline the same one i had on the 350 and the same as you tim but i did use the 350 spacer plate whould that make any probs the 500 one made the cairclener hit the bonnet.
also i was told that the mix screw should only be one turn whould this sound right as she wont run under 1 3/4
cheers GSpack

 

[xctasy]

G/Spack said:-

GEZ thats a bit to check on ,I,ll wait to see how yours go tim before i go up in jets .

Good idea. I can't help but think the reason your having problems are because of too smaller main jets because the power valve oriface restriction is wrong for the engine size. It's something few people look into. I'd be picking that this is the problem

One of those 8 is the problem.

Holley 7448's came with piddly 122-61 Primary (main)jets, 125-85 power valve, and a primary discharge nozzle of 31 thou. Most 186/202 Holdens run in the 63 to 65 main jet range with this carb.

Holley 4412's came with piddly 122-73 Primary (main)jets, 125-50 power valve, and a primary discharge nozzle of 28 thou.

David Vizard used the stock 7448 350 Holley with a 56 main jet, and got 132 hp (net flywheel). He used a 17 thou power valve orifice, and a 40 or 45 power valve. As soon as the same engine got a 500 Holley, it ran the same power valve oriface restriction, power valve, and a 74 main jet. Hp was 6 extra at 138 , but the engine was a fairly mild Pinto Two-liter. I've got to say, when I used the 500 Holley on my Cortina, I just used it stock. There was lots of eye-watering rich idle.

Vizards' quotes centre around the power valve oriface restriction, and the primary discharge nozzle isn't the same thing.

This is from Page 69 of the How to Modify Ford S.O.H.C. Engines, 1984 from Fountain Press, ISBN 0 86343 0856.

Calibrating the 350 or 500 Holley for a two-litre engine is very simple if you bear in mind one thing most of these carburettors are built for engines of at least double the capacity. As such, the power valve restriction oriface is normally way too large for a two-litre engine. For most street applications on a Pinto engine or any two-litre Ford OHC engine this oriface needs to be around 17-20 thou diameter. If it is too large, when the power valve comes into operation, the mixture will be vey rich and power will take a nose-dive. And, if you lean out the main jet to compensate, you run into drivability problems at part-throttle. Apart form this, recalibrating the Holley for use on the Pinto engine seams a straightforward operation. Not only does it achieve good bhp gains, it also provides with regard to emissions, a very clean running engine.

Sounds like your problem guys!

And this, from page 73-74 , is a real jewel:-

Short durationm high lift street cams and ported heads can produce sharp induction pulses. In turn these porduce air flow velocities, in a 350 Holley two-barrel carb, high enough to compensate for driving problems stemming from large throttle bores. But cam timing is touchy. If duration is just a little too long, drivability may suffer. With some hot street cams and two barrel installations, drivaility can be seriously affected by as little as 4 degrees two much advance on the camshaft. This situation tends to be less critical if a four barrel carburettor is used.

Yeah, yeah, piddly two-liter stuff, but hey, were dealing with something a lot smaller than a 2-bbl 327 or 396.

Devils in the detail. Once you;ve waded through the crap, you'll find this is the key. Print this out, and check it with your carby tuner.

 

[xctasy]

Note that Holley use basic jetting which changes in proportion to the carb cfm. A stock 350 came with 61 main jet, the 500 had a 73 main jet. The area of a main jet may be ((61/2)^2)*3.14 or 2922 units for the 350, and((73/2)^2)*3.14 or 4185 units for the 500. Thats a 43% increase in area, which is propertional exactly to the difference in size between a 350 and 500 Holley (also 43%).

Applying the fuzzy logic, the base 350 on a six with the right restrictor oriface, maybe about 65. This is about about 3318 units of jet area. A 500 should run in at 1.43 times this, 4745 units. You have to divide by 3.14, take the square root, and multiply by two. Jet size is ~78. Go for a 50 or 45 power valve, because Holley tends to drop the power valve actuation pressure on bigger carbs.

Just found another missing link #2300 carb. The 9647 must have been for Ford V8's. This ran a Holley PN 122-81 primary, so that 78 seems just fine guys. The power valve is down to PN 125-45, which is 45! The primary discharge nozzle is 40 thou! This must have been for a big V8!

Looking at it proportion wise from combos that work, I 'd say a 22 thou power valve restriction oriface, if it is able to be created by bushing, may be the caper.

It's like green eggs and ham. Try it and you'll like it.

 

[Anonymous]

Amazing, Thanks
GS packs 250 2V is 208 at 50 .420 lift (4200 rpm) mine is 204 at 50 .417 lift (4000 rpm). He has had some considerable trouble with the 500 I have not (interesting to note after youre quote in the above).
Everything else cars, engines, are the same.
I only downsized my jets for economy and it worked, I am wondering now if 68 is too small and think I will go back to 71. Think I may have lost some power as it seemed to run out of puff at around 3500 to 4000 and the acceleration seemed more instant with the bigger jets I just did not think the 13 litres per 100 on the open road was very good economy. Actually I like the idea of a carb with a ventury size in between a 350 and a 500 but that flows as much as a 500.
I am not going with the 600 Holley idea after I read in Aussie sixes section on Ultra flow manifolds and fuel dispersion.
My car idles beautifully with a slight rock in the car, I may still get the idle sleeved. Or wait and see if GS pack fixes his first.
I would not have thought that 4 degrees (=200 rpm) would be enough to make any difference, but it seems that it does. What did Ausssie seven mains say "a 500 is OK on a stocker it is not with a cam" refering to the 250 2V. My cam is close to a stock cam at least very close to a stock Cross flow EFI cam. The proof is in the pudding.
Regards, Aussie seven mains

 

[xctasy]

Your head has had some work on the exhast ports, hasn't it? If there is some restriction on reversion in two engines otherwise similar, then one may suffer tractorbility problems while the other is just fine. All comes down to if the standing wave at curb idle or just off the curb idle goes back up the inlet tract to the carby venturi. Even a little port mismatching (as little as 40 thou, on either the intake or exhast.) can help a huge amount if the intake manifold is smaller tan the intake port. It's only a factor in cars with street cams with aggressive duration as the valve opens. Not an issue with wild racing cams, where a car won't idle anyway!

Hey, found a few more standard Holley #2300's. The 4782, a 355 cfm carb with a different booster venturi, has 64 mains, and 65 power valve, and 31 thou primary discharge. The 4783 is another 500 cfm, with an 82 main, and 28 thou primary discharge. No reading for the standard power valve with this combo.

Hope this helps. To recap, there are two 2-bbl 350/355 CFM #2300's to choose from 7448, or 4782. None is a six cylinder carb with an authentic Holley calibration.

There are four 500 cfm #2300's to choose from 4412, 4412-1 (with kickdown attachment), 4783 and the 9647. Holley never had a calibration just for our 200/250 sixes.

There are the Barry Grant's three specials of the 500 cfm, one which can be used on alcohol.

Then there is the rare as hens teeth 650 cfm PN 6425.

All have main jets ranging from as little as 61 to as much as 82, with any number of valid variations from 56 to whatever fits. There are many different recomendations on what power valve oriface restrictor size should be used, from as little as 17 thou to as much as 40 thou. Don't be afraid to experiment with bigger jets, I'm certain these won't kill any fuel economy you have. Going to softer power valves and the restrictors should fix the rich idle. Then if you can get someone to make up a couple of press fit power valve oriface jets, and grab some 74 and 78 mains to play with (most of the V8 guys should have a few spare jets like this for there #4150 780's or 850's on 350/351's that they should loan you), you will get the drivability right.

 

[Anonymous]

Thanks
I didnt think that would make much differance. Now that you mention it yes mine has been ported significantly on the exhaust, mine is a 2 1/2 exhaust GS packs is 2 1/4. Also if memory serves me correctly I think the configeration of his headers/extractors is different and mine although off centre a bit on some ports, were all bigger.
All that said I dont think I would be able to advance my duration without big problems unless I had velocity stack under the carb.

 

[Anonymous]

Thanks, Ill go with the bigger jets. And find out If anyone knows how to sleave the idle. Most of the people down here start looking at you with strange looks when you start trying to ask for this sort of thing.
Cheers!

 

[xctasy]

I think I should have been more carefull with the lingo.

Be real carefull with the terminology, Tim. I spent five hours today trying to find out where on the carby this restrictor thingamagig is. There are twelve jets and restrictors it could be, so a smart a$$ counter jerk could embarras you easily. It is in fact two holes on the main body of the carb with the float bowl removed. The removal of the power vlave, with a 1 inch socket, shows two anular holes. Measure the diameter of these with some fuse wire or specialised gauge wires or drills from a engineering supplier.

You'd sound like a proper twot asking for a Power Valve Channel Restrictor, or PVCR. There are numerous references to the term PVCR, but its only on page 32, 48 and 65 of the 120-odd page book by Dave Emanuel that you find out what it is. (Beg steel or borrow 'Super Tunning & Modifying Holley Carburetors', ISBN 0-931472-08-3) Then you have to wait till Page32, 50 and 65 to see the pictures, and then battle 15 more pages of crud to get some excellent calculations which are of no jolly use unless you are running the double pumper 4150 series 4-bbl.

uGGGGGGHHHhhh!

Get the book and point to it with a pen and find a machinist who can create two bushes which will fit the existing hole which may be between 21 and 120 thou in diameter. If it is 21 thou, I'll eat my hat. Drill oversize, plug it with a small insert made of brass, and then drill to the required size (22 thou). The power valve should be the smallest type, and use 45 for a start (kicks in a 4.5" Hg of vaccum, or 15 kPa.)

The PVCR sizes are not listed, and all I've been able to garner is that the #4160 390 cfm is 21 thou. Others are different, as Holley tailors the thing to suit the application, right up to 120 thou. According to Offenhauser, when shoved on a 171 cube V6, these 4-bbl carbs need to have the PVCR enlarged to 40 by drilling, but that's because they wanted to use very small jets, and they coverted a heck of a lot of other things too.

Vizard doesn't go into any details or show photos, but is adamant on the need to restrict because of what you guys are noticing.

 

[Anonymous]

Well i just thought i let you know that i changed the dizzy and put a electronic one in and i,ll be damed the car is running ahell alot better it actuly idles but the fuel smell is still stronge . i,ll see if there are any good holley guys here in brissy tim and see what thay can do going by XECUTE,S recommandtions
CHEERS GSpack

 

[Anonymous]

Execute
Went to get a 78 jet from a carb re-builder. he showed me his book and said 73 is biggest 500 Holley came with (doupt this). So I eventually settled on 74 it does go better. He then told me I was likely to have a 55 power valve in my 500 and that a 45 would cause it to use more fuel as it supplies more fuel sooner than a higher number (now I was confused).
He then went on to tell me that the power valve only works until the vacuum reaches certain point and the main jets activate. He tells me that some cars with very lumpy cams have no power valves and that at the opposite end a standard Holden carb has 85 an power valve.

 

[xctasy]

Aussie may have had different carbies to the US mob. Please check with what the V8 guys did with a 500 cfm 2-bbl carb on a 307, 327 or sometimes is retrofitted to a 350. Be very supprised if it wasn't 81 like the Holley manul says.

But it comes down to how the tunner gets the carb running. I haven't seen a Holley 2-bbl yet that has been near a dyno tunner. Lazy beggars expect the carb settings just to drop out of the sky, and get a king hit. Doesn't work that way. Guite often, high vaccum creates the ablity to run very small jets like what you guys are doing, but if it's all based on an idle ciruit that's too rich, then you get a problem with flat-spots. The PVCR is the next port of call, so to speak. Often, guys get out the drill and do the throttle butterflies, and then try a few other changes, and all of a sudden, no two 500 cfm carbs are alike. In NZ, many parts come direct from the US, bypassing Aussie suppliers.


If the guy says nothing bigger than 73, then maybee thats the truth for Aussie 500 cfm carbs. But a 318, Valiant 265, or 289 or 302 2v got Holley swaps all the time. My friend Tony had one on his 1977 XC Fairmont 500 with a 4.9 Cleveland, and it ran 78's. Sure, it had dual pipes, but it was otherwise stock.

What part number is on it?

 

[Anonymous]

http://www.holley.com/HiOctn/ProdLine/P ... 55001.html

would this be a good thing to use?

don

 

[xctasy]

Sure would. I saw the kit about four years back in a Hot Rod article. I think Jet made them (no, it's not a play on words...)

I think the air cleaner needs a little hammeing, as the carb is now 4160 size, not 4150.

Basically, its like the plate on a Holley 4160 or 4175 or 4180.